Detect HTML Attributes

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Solution{


	public static void main(String[] args) {
		/* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
		
		Scanner in = new Scanner(System.in);
		int n = Integer.parseInt(in.nextLine());
		String string;
		String regexOnlyTag = "[<][\\w]+[>]";
		String regexTagAttr2 = "[<][^>]+";
		String regexTagWithAttr = "[<][\\w]+[ ]+[\\w]+";
		String regexTagWithAttrNext = "[ ][\\w]+[=]";
		Pattern tagPattern = Pattern.compile(regexOnlyTag);
		Pattern tagWithAttrPattern2 = Pattern.compile(regexTagAttr2);
		Pattern tagWithAttrPattern = Pattern.compile(regexTagWithAttr);
		Pattern tagWithAttrPatternNext = Pattern.compile(regexTagWithAttrNext);
		Map<String, Set<String>> tagMap = new HashMap<String, Set<String>>();
		for (int i = 0; i < n; i++)
		{
			string = in.nextLine();
			Matcher tagMatcher = tagPattern.matcher(string);
			Matcher tagWithAttrMatcher2 = tagWithAttrPattern2.matcher(string);

			while(tagMatcher.find())
			{
				String temp = string.substring(tagMatcher.start(), tagMatcher.end());
				temp = temp.trim();
				temp = temp.replaceAll("[<|>]", "");
				if(!tagMap.containsKey(temp))
					tagMap.put(temp, new HashSet<String>());
			}
			while(tagWithAttrMatcher2.find())
			{
				
				String temp = string.substring(tagWithAttrMatcher2.start(), tagWithAttrMatcher2.end());
				temp = temp.trim();
				temp = temp.replaceAll("[<|>]", "");
				String[] tempArray = temp.split("[\\W]");
				tempArray[0] = tempArray[0].trim();
				Matcher tagWithAttrMatcherNext = tagWithAttrPatternNext.matcher(temp);
				while(tagWithAttrMatcherNext.find())
				{
					String temp2 = temp.substring(tagWithAttrMatcherNext.start()+1, tagWithAttrMatcherNext.end()-1);
					Set<String> set;
					if(!tagMap.containsKey(tempArray[0]))
					{
						set = new HashSet<String>();
						tagMap.put(tempArray[0], set);
					}
					else
						set = tagMap.get(tempArray[0]);
					set.add(temp2);
				}
			}
			
		}
		// sort the map based on key field
		Map<String, Set<String>> sortedTagMap = new TreeMap<String, Set<String>>(tagMap);
		for(Map.Entry<String, Set<String>> entry : sortedTagMap.entrySet())
		{
			Set<String> set = entry.getValue();
			Set<String> sortedSet = new TreeSet<String>(set);
			StringBuffer strbuff = new StringBuffer();
			strbuff.append(entry.getKey()+":");
			if(!sortedSet.isEmpty())
			{
				for(String item : sortedSet)
					strbuff.append(item+",");
				strbuff.deleteCharAt(strbuff.length() - 1);
			}
			System.out.println(strbuff.toString());
		}
		
	}
}